Integrated circuits and semiconductor devices are fabricated by performing a number of fabrication processes that form various components and regions, such as source/drain regions, gate structures, isolation regions, and the like. One set of structures formed and/or present in semiconductor devices are metallization layers, which provide electrical connections between various components within the devices and external connections.
The metallization layers typically comprise trenches and vias formed in single or dual damascene fabrication processes. The trenches and vias are comprised of conductive materials and are separated by insulating layers comprised of dielectric material to, for example, mitigate crosstalk between various layers. The trenches and vias form interconnects or pathways through the dielectric material.
As device sizes continue to shrink to enable fast operational speeds and higher densities, problems can be encountered for metallization layers. Higher current tends to pass through smaller trenches and vias. As a result, problems such as electromigration can occur. Electromigration is the movement of conductive or metal ions as a result of current passing there through. In, for example, copper vias, electromigration can cause copper ions to migrate and result in formation of void regions within the copper vias. Generally, for electromigration, a compressive stress increases in an anode region of a via while a tensile stress increases in a cathode region. There tends to be a movement of metal or conductive material that leads to void formation in locations of tensile stress.